Winning ways: Wainer isn't a dreamer; he's a doer. Since cofounding DigitalOcean, the cloud computing company has gained 150,000 customers in a half year and one million website visits per week. In addition, 60% of its customers come from word of mouth.

Defining moment: I was 26 at the time, and I was working for an ad agency as the director of marketing. I was working from home…and I just felt lost and confused. I clearly wasn't happy, [and] I wasn't learning. I called the show This Week in Startups, and [host] Jason Calacanis gave me some great advice: “It's better to be the worst benchwarmer on the Knicks than to be the best player at the YMCA rec. center.” He basically encouraged me to take a risk and to go out and start a company of my own…and join an accelerator program.… I actually took his advice and did that.

Words to live by: “‘Always be testing.' I also like the motto ‘Iterate faster.'”

Head swivel: “After doing an analysis recently we found that a majority of our new customers come in through the referral program. So, we're currently in the midst of revamping it and enhancing the program to drive more referrals.”

Good advice: “I'm a big believer in learning by doing. You can read until you're blue in the face. It's when you execute, test, actually do it, and fail is when you really learn.”

First job: “I was selling things when I was five years old; I used to collect four leaf clovers, laminate them, and sell them to kids at school [for $5 a piece].

“My first summer job [was at 13] working as a Web designer/developer for a baseball software program. I built and designed its website. That's when I really started to learn about website development and design…. That was the foundation I needed [in terms of] designing and building the first DigitalOcean website. Not only did I do the marketing for DigitalOcean, but I also designed the website.”

On your nightstand: “I really like the book Rework by Jason Fried and David Heinemeier Hansson of 37signals [now software company Basecamp]. It breaks down in a simplified way and it paints a clear picture of what matters, what's really important in driving a business forward; [how] to focus on the important things, not to get bogged down by the little things, and to be...agile and lean. I think that metrology of just getting stuff done was impactful for me when I read that book early on in my career.”

Favorite mobile app: The ones that I use the most are Uber, Waze, and Slack.com. Uber is incredible in how it's made transportation so easy and accessible. And it's making $20 million a week. I always like Waze for navigation when I'm driving. It tells you the shortest ways to get to your destination. Slack is actually a communication tool for companies, and it works really well when you have teams and you want to share files and communicate within your company.